Structural steel members are widely used in the construction of buildings, bridges, billboards, signs, piers, foundations, retaining walls and similar structures. These structures are typically built with a steel fine to which floors, walls, panels and other elements are connected. These steel frames are typically constructed from structural steel members which are made with standard cross-sectional shapes which are especially suited for particular applications.
One cross-sectional shape that is particularly common is the ubiquitous "I-beam." The "I" shaped cross-section of the I-beam has a particularly high moment of inertia for its size and weight making it extremely useful as a beam for carrying loads. This shape also makes it resistant to buckling when used as a column or brace. Several variations of the I-beam have become standard in the industry and are shown in FIG. 1. The "W" shapes or wide-flange sections 2, the "M" shapes or miscellaneous flange sections 4, the "S" shapes or standard flange sections 6 and the "HP" shapes or bearing pile sections 8 all have the characteristic "I" shape with its protruding flanges 16 and interior web 18. Structural channels 10 and angles 9 also have a shape with protruding flanges 16, however, on channel sections 10 and angles 9 the flanges protrude from only one side of the web. Structural "T " shapes 12 also have protruding flanges as do numerous other composite shapes 14 which may be fabricated for special purposes.
Connections between structural steel members are typically made using multiple bolts which are spaced apart in specific patterns with precise spacing dimensions or using welds along with gussets and brackets to form the connection. Connections of structural steel members may be simple connections, as shown in FIGS. 2A through 2D where shear forces are transferred, but little bending moment is transferred in the connection or they may be more complicated moment resisting connections, as shown in FIGS. 2E and 2F where substantial bending moment and shear forces are transferred in the connection. Both types of connections typically require numerous bolts 20 arranged in patterns 22 with standard spacing requirements.
The fabrication of these bolted connections begins in the shop where beams, columns and other members are cut, welded, drilled and otherwise prepared for assembly on a construction site. Often clips, gussets, brackets, stiffeners, plates and other elements are cut and welded or bolted to one member and drilled for assembly to an accompanying member with bolts which are inserted on site. This construction fabrication requires precise measurement of bolt and other element locations so that field assembly will flow smoothly without interruption. Accordingly, bolt and weld locations must be laid out with precision, accuracy and efficiency.
While bolt locations and patterns vary for different connections, grades of steel and member shapes, the prevalence of certain grades of steel and certain structural shapes makes some bolt spacing patterns especially common. Bolt spacings which are commonly found in structural steel connections are 3" and 51/2" . In laying out these patterns, measurements must often be made from the top of the top flange on the beam to a point on the beam web. This requires a steelworker to measure around the top flange and place an accurate mark on the web of the steel member. This requires several steps and multiple tools using conventional layout tools. A tool which allows this measurement to be performed in one step can drastically increase productivity and significantly reduce the possibility of error.
Large structural steel members can be extremely expensive and an incorrectly placed bolt pattern can damage or completely ruin one of these members causing extensive financial loss. Furthermore, a mistake may not be discovered until the steel member is raised to the top of a high-rise building project with a crane. At this point many man-hours may have been wasted in transporting and placing the steel member only to discover that the member is defectively fabricated. This type of mistake can be extremely costly in wasted man-hours and material. Consequently, steelworkers are typically highly skilled workers who gain extensive experience before receiving responsibility for connection layout.
Due to the heightened responsibility and the highly skilled nature of the job, steel workers typically receive higher wages than the majority of construction workers. A steelworker who can work quickly and efficiently is, therefore, a tremendous asset. Correspondingly, a tool which can improve steelworker speed and efficiency and increase accuracy and precision is also a tremendous asset.